/**
 * Copyright © 2008, EMC Corporation.
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 *
 *     + Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     + Redistributions in binary form must reproduce the above copyright 
 *       notice, this list of conditions and the following disclaimer in the 
 *       documentation and/or other materials provided with the distribution.
 *     + The name of EMC Corporation may not be used to endorse or promote 
 *       products derived from this software without specific prior written 
 *       permission.
 *
 *      THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 *      "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 
 *      TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
 *      PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS 
 *      BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 *      CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 *      SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 *      INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 *      CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 *      ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 *      POSSIBILITY OF SUCH DAMAGE.
 */
package com.emc.esu.api {
	/**
	 * An extent specifies a portion of an object to read or write.  It contains
	 * a starting offset and a number of bytes to read or write.
	 */
	public class Extent {

	    /**
	     * A static instance representing an entire object's content.
	     */
	    public static const ALL_CONTENT:Extent = new Extent( -1, -1 );
	    
	    private var offset:Number;
	    private var size:Number;
	    
	    /**
	     * Creates a new extent
	     * @param offset the starting offset in the object in bytes, 
	     * starting with 0.  Use -1 to represent the entire object.
	     * @param size the number of bytes to transfer.  Use -1 to represent
	     * the entire object.
	     */
	    public function Extent( offset:Number, size:Number ) {
            this.offset = offset;
            this.size = size;
	    }
	    
	    /**
	     * Returns the size of the extent.
	     * @return the extent's size
	     */
	    public function getSize():Number {
            return this.size;
	    }
	    
	    /**
	     * Returns the starting offset of the extent
	     * @return the extent's starting offset
	     */
	    public function getOffset():Number {
            return this.offset;
	    }
	
	    /**
	     * Compares two extents.  Returns true if they are equal.
	     */
	    public function equals( obj:Object ):Boolean {
	        if( !(obj is Extent ) ) {
	            return false;
	        }
	        
	        var b:Extent = Extent(obj);
	        return b.getOffset() == offset && b.getSize() == size;
	    }
	    

	}
}